1. Field of the Invention
The present invention concerns an improved process for rendering a cell-containing composition substantially free of enveloped and non-enveloped viruses contained therein without substantial disruption or inactivation of cells contained therein and without significant loss of labile proteins or other valuable biological components also contained therein.
2. Description of the Related Art
Viral inactivation of cell-containing compositions by treatment with irradiation, e.g., UV or visible light, a photosensitizer compound and, optionally, one or more quencher compounds has been described in the applications and patents mentioned above, the entire disclosures of which are hereby incorporated by reference. Such treatments are known to cause K.sup.+ leakage from red cells. See, e.g., J. van Steveninck et al., 1985, "The influence of cupric ions on porphyrin-induced photodynamic membrane damage in human red blood cells", Biochim. Biophys. Acta., 821: 1-7.
Irradiation is used in other contexts involving cell-containing compositions, for example, ionizing radiation, e.g., .gamma.-irradiation or X-irradiation, to prevent graft-versus-host disease in immunodeficient patients. For this particular purpose, collected red cells increasingly are being stored for variable periods in transfusion service inventories following irradiation. Other reports of elevated K.sup.+ in irradiated, stored RBC, have recently surfaced. See, for example, Elaine K. Jeter et al., 1991, "Effects of irradiation on red cells stored in CPDA-1 and CPD-ADSOL (AS-1)", Ann. Clin. Lab. Sci., 21: 177-186; and A. M. Ramirez et al., 1987, "High potassium levels in stored irradiated blood", Transfusion, 27: 444-445. For blood centers offering red cell irradiation, prolonged storage following irradiation may expose selected patient populations to a significant K.sup.+ load following transfusion.
It also is known that morphological deformations of erythrocytes are induced by hematoporphyrin--a photosensitizer compound--and light. See, for example, Bruria Lev et al., 1993, "Morphological Deformations of Erythrocytes Induced by Hematoporphyrin and Light", Lasers in the Life Sciences, 5: 219-230. Specifically, hematoporphyrin-bound cells displayed a marked reduction in membranal negative-charges and sialic acid residues on their cell membranes.